Overspeed governors and elevator door safety edges have commonly used mechanically actuated switches to indicate interference with the normal movement of the car or door. The indication is in the form of an electric signal which deenergizes and brakes the main drive motor in the case of the car or which reverses the door drive in the case of the door. One disadvantage of these prior art controls has been the relatively short life of the switch contacts due to mechanical and electrical wear. A typical problem with the prior art safety edge systems for control of the door movement is that the frequent flexing of the electric cables connected between the doors and the drive system creates maintenance problems by causing frequent breakdowns of the system. It would, therefore, be desirable to provide a control system which when used for door control detects an interference with the movement of the door without employing sensors carried by the door itself, which sensors have necessitated the use of flexible cables, sliding contacts or the like.